The NFL guarantees veteran contracts that are signed before the start of week 1 which is why every year there is a list of veteran players who remain unsigned until the season starts. This year is obviously no different.
The way the system works is; teams are able to sign veterans after they finish “their” first game of the season. Since the Saints and Vikings will play their first game tonight, they will have at least a three-day advantage over the rest of the NFL teams.
To be fair, it should be setup so that all teams have an equal amount of negotiating time to negotiate with veteran players. Since the NFL chooses what teams will play in the first game of the year, they are giving them a distinct advantage to sign veteran players that could help bolster their teams depth.
We’ll have to see if the Saints and Vikings take advantage of this following tonight’s game.